Maintain an Active Social LifeThe love and companionship of others is integral to aging gracefully. It's well established that isolation or perceived loneliness is associated with conditions that age the body and put it at greater risk for age-related diseases. Loneliness has been found to raise blood pressure, affect sleep quality, and increase the production of the stress hormone cortisol. On the other hand, friendship has been associated with decreases in depression, increases in self-esteem, and better stress management.

Data from the Australian Longitudinal Study of Aging has shown that people age 70 and older who have an active social life can live 22 percent longer than those with a less active social life. And in 2008, researchers at Harvard's School of Public Health found that socially active seniors had a slower rate of memory decline than their peers.

But if I had to boil down all the sociopsychological factors that help you age well into one word, it would be happiness. It's happiness—that joie de vivre—that makes all the difference. The good news is that many people actually become happier as they get older. When researchers at the Centers for Disease Control and Prevention surveyed different age groups, people in their early 20s reported feeling sad an average of 3.4 days per month while people ages 65 to 74 felt sad only 2.4 days. Cheers!